Improvement in rotary pressure-blowers



L. PALMER &. l. w. KNOX,

Rotary Pressure Blowers.

N0.]66,295, PatentedAug.3,1875.

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N. PETERS. PHOTO-UTHOGRAPHER. WASHINGTON D UNITED STATES PATENT Orrron.

WALES L. PALMER AND ISRAEL W. KNOX, OF SAN FRANCISCO, GAL.

IMPROVEMENT IN ROTARY PRESSURE-BLOWERS.

Specification forming part of Letters Patent No. 166,295, dated August3, 1875; application filed July 13, 1875.

To all whom it may concern:

Be it known that we, WALES L. PALMER and ISRAEL W. KNOX, of SanFrancisco city and county, State of California, have invented anImproved Rotary Pressure-Blower; and we do hereby declare the followingdescription and accompanying drawings are sufficient to enable anyperson skilled in the artor science to which it most nearly appertainsto make and use our said invention or improvement without furtherinvention or experiment.

Our invention relates to certain improvements in pressure-blowers; andit consists in constructing the arms of the two pistons or drivers uponcertain peculiar curves, by which we are enabled to maintain'a close fitbetween the circumferences of the two drivers, and thus utilize ourmachine upon blast-furnaces, and in other places where a positive forceis necessary to produce sufficient blast.

Referring to the accompanying drawing for a more complete explanation ofour invention, Figure l is an end view or pattern of our blower-pistons.

In the construction of the so-called'pressureblowers, as heretoforemade, the arcs of circles have been used to form the shapes of thedrivers or pistons, and by varying the length of the chords, while thesame arcs are used for the sides and ends, an attempt has been made toobtain a perfect fit between the two pistons at all points of theirrevolution. This has not been effected, however, and as aconsequencethis class of .blowers have been failures wherever there has been anyback pressure developed.

In order to overcome these difficulties we construct the heads and sidesof our pistons upon epicyoloidal curves, as follows: a is the center ofmotion of one of the pistons, and b is the pitch line or circle. Inorder to form the heads 0 c of the pistons we. make a wheel or circle,d, the diameter of which is one-fourth the diameter of the pitch-circle.Equal chords 0 c are drawnwithin the pitch-circle, forming an exactsquare. The circle d is placed with its tracing'point upon the junctionof any two of the chords, and is then made to revolve once upon theoutside of the pitch-circle, when the tracing-point will have describedthe epicycloid required, and will stop at the point of junction of itschord and the next one. The opposite head 0 will be formed in the samemanner. The sides g g of the pistons are traced by revolving the wheel(1 upon the inside of the pitch-circle upon each side, between thetermiiii of the heads 0, thus forming a continuous curve.

It will be found, when a blower of this construction is set up, thatevery point of the periphery of the two pistons will exactly meet asthey rotate, and the fit will be so perfect that the machine becomes apressure-blower capable of working against a resistance without slip orwaste.

Having thus described our invention, what we claim as new, and desire tosecure by Letters Patent, is

l. The rotating pistons, each consisting of the convex heads 0 c and theconcave sides g 9, said heads and sides being constructed uponepicycloidal curves, for the purpose of making an exact fit between thepistons as they rotate, substantially as herein described.

2. The rotating pistons, each consisting of the convex heads 0 c and theconcave sides 9 g, said heads and sides being constructed uponepicycloidal curves, and having the chords of the heads 0 c and thesides 9 g of equal length,

substantially as herein described.

Witnesses:

GEO. H. STRONG, O. M. RICHARDSON.

